The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
A typical planetary gear assembly includes a carrier that supports at least one pinion pin. A pinion gear is rotatably mounted on the pinion pin and engages a ring gear and a sun gear. In the process of assembling the typical planetary gear assembly, the pinion pin is pressed into a pinion pin hole located in the carrier. The pin is then staked at both ends by a stake punch. This staking process involves plasticly deforming the relatively soft region at the ends of the pin using the stake punch to restrain the pin from sliding and rotating relative to the carrier. In addition, the staked pin is required to remain in place when subjected to specified axial forces. Since staking involves plastic deformation of the pin, a relatively high stake force is required. However, a high stake force can also lead to undesired stresses and distortion of the pin and carrier as well as a reduced life of the staking tool. This is especially critical for hollow pinion pins.
Accordingly, stake punches have been designed to attempt to maximize retention forces while minimizing undesired stresses and pin distortion. Typical stake punches can generally include a stake face that is either flat, spherical, or conical, While useful for their intended purpose, there is room in the art for an improved stake punch that maximizes retention forces while minimizing undesired stresses and pin distortion.